Developed by Christopher Clayton Hutton at MI9, this is the final design of the miniature escape compass and the smallest measuring just 5mm in diameter and 2mm tall. The case is solid brass and fitted with a central 'pin' onto which the rotor is placed. This is in the form of a simple black painted metal disc marked with a single luminous dot to indicate North. Being so tiny this compass could easily be concealed inside such things as pencils, pens, pipes, cigarettes etc. It would no doubt have been incredibly challenging to use but is now one of the rarest compasses to find. In very good used condition. Stock code E27027.